Irish troops,
including 1,000 men sent by Foisotte, fought during the siege
of Barcelona (1651-1652). In the following year, 2,000-3,000
Irishmen took part in the failed campaign against Guyenne,
where 500 lost their lives and a similar number deserted to
the enemy. The Spaniards landed at the Gironde Estuary but
were unable to relieve Bordeaux (besieged by the French army).
They managed to hold out for six months in spite of severe
supply problems and returned to Spain at the end of the year.
Half of the 4,000 survivors were Irish.

Portugal

Irish soldiers
were also active in the Portuguese war but in smaller numbers.
In 1644, a regiment of 'Naciones' (i.e., non-Spanish troops)
including Irishmen fought at the battle of Montijo. 600 Irish
troops took part in the offensive of 1653, in the Tercios
commanded by William Dongan and Bernard Patrick. The latter
was killed at the battle of Olivenza. The Irish were given
praise for their heroism in the defence of Badajoz. By 1662
there was no longer an Irish Tercio because of the small
numbers of soldiers of that nationality, but a number of
Irishmen took part in the last two campaigns of the war which
culminated in the defeats of Ameixial (1663) and Villaviciosa
(1665).

In 1653, the
survivors of the army which Owen Roe O'Neill had led during
the Irish rebellion arrived in La Coruña under Colonels
O'Reilly, O'Ferral and O'Rourke. Their departure from Ireland
had been the result of negotiations between Ambassador
Cárdenas and Captain (later Major) George Walters. Madrid
intended to employ them against Portugal but nothing came of
it. Galicia was not a good route to invade Portugal as the
natural path of advance was through Extremadura.

The local
authorities of La Coruña only allowed two of the seven vessels
to land (1',000 men under O'Reilly) and the following year
these troops were transferred to the Army of Flanders. The
remaining ships (1,900 soldiers) had to proceed to Pasajes,
where they linked up with another Irish contingent of 800 men.
In the weeks that followed, many died of hunger or disease and
others became beggars. The bulk of the survivors were sent to
reinforce the ill-fated expeditionary force in Guyenne, but
others remained in precarious billets in northern Spain. Their
commander, Thaddeus (Tadhg) O'Rourke, travelled to Madrid in
March 1654 to complain about the conditions and was finally
given orders to muster his men and move to Zaragoza. 1,100 men
had gone into winter quarters in Cantabria in the autumn of
1653. By January, only 540 were still under the colours (the
remaining had died or deserted).

So many
Irishmen had become scattered in northern Spain that in 1654
Madrid sent two trusted servants to re-assemble them into an
army. One of them was Colonel Hugh O'Neill, a leader of the
Irish rebellion who had been released from the Tower of London
by the intervention of Ambassador Cárdenas. The other was the
ubiquitous François Foisotte.